spread in cast rb weights

[jamesthomas]

 How much spread in .50 cal. cast rb weights should you allow for ? I'm using some roofing lead I've have so it's real soft lead.

[Standing Bear]

For serious match shooting and hunting (never can tell when you have a small hole in the brush to shoot thru):

On my .40s I use heaviest minus 1 gr.  .40 cal ball weighs about 93 gr.    1/93 = .0107 or 1.1% variation

On 50s and larger, heaviest minus 2gr.  .50 cal ball weighs about 180 gr.  2/180 = .011 or 1.1% variation.

TC

[Daryl]

Actual weights of the balls varries with different moulds, even of the same make and design, so you can't try to match what someone else's mould throws.  There isn't a LOT of difference, just enough to make actual numbers non-reliable.

Seems to me cast bullet accuracy shooters throw away light and heaviest bullets - but one must weigh them to be certain to use a wight for the peorly cast ones, not balls from slightly open blocks (lead splash on faces), which will add weight.

Personally, I havee't weighed balls since the 70's, but if going into a serious match, might start anew.

TC's 1 and 2 gr. sounds reasonable for .40 and .50 - perhaps 1 1/2gr.  for .45, however if I was going to weigh balls, I'd be looking at 1/2gr. max variation, then testing both, one against the other for accuracy to see what actual difference there was between average , non-weighed balls and those I'd weighed.

[SCLoyalist]

Work for 1 gr or less and especially weed out the light ones that may have air bubbles inside making them light.   

I couldn't find any cast 50 cal balls, but I weighed five .530 RBs and the extreme spread in weights was less than 1 grain.

A 490 RB should weigh around 177 gr,   a .495 one should weigh around 182.5, a 498 ball 186 gr.    Five .495 swaged Hornady RB that I just weighed had an average weight close to 175 grains, so either my scale is off, or Hornady didn't swage pure lead.   The point is, you may be casting with different stuff from time to time or your scale may show some bias error, so it's best to weigh 5 or 10 balls (I think the last 5 or 10 balls) from your casting session, compute their average weight and look for deviations from that.  Set your scale to that average value and start putting cast balls on one at a time.  You don't have to balance the scale for each one, but you'll be able to spot the obviously light balls and can drop them back into the pot.  You may find a couple of heavy balls too, but any impurity is probably going to be lighter than pure lead, so a heavy ball may have a ridge on it where the blocks didn't mate right, or a pronounced sprue that you'd want to pitch back into the pot.

[Roger Fisher]

I find an average and then if the arm floats (on my mechanical) scale they are good to go...

[Daryl]

I had a DC Ohaus mould in .495 for my .50 back in the 80's. Those RB's had a tangental cuttoff, that measured .495 from the centre of the sprue flat to the bottom of the ball and were .495" in diameter, across the seam and on the sides. Both blocks were identical, something not normal in today's moulds.  They weighed 184.0gr. in the alloy I had at the time- telephaone casings with the tinned ends cut off - only the pure lead centre sections were used for balls.
Measuring form the centre of the sprue cuttoff down tot he bottom of the ball today will usually show 2 to 4 thou smaller dimenson than what's written on the blocks for the size.

[beleg2]

Hi,
I'm not an expert, not even look like and expert 
The way I get peace of mind is sorting  ball by weight.
The way I do it is simple even thou it takes some time.
After casting a lot, I set my scale at 180 gr for example and sort ball in two groups according to the scale arm over the  line or under the line.
Then set  the scale at 180.5 gr and do the same.
This way, I get the ball sort in groups with no more than .5 grains difference.
Finally, take the biggest two or three groups together.
This way I can sort lighter balls and those heavier ones.
Hope this helps.
Martin

[Maven]

"Actual weights of the balls varries with different moulds, even of the same make and design, so you can't try to match what someone else's mould throws.  There isn't a LOT of difference, just enough to make actual numbers non-reliable."   ---Daryl

What Daryl said is true.  E.g., I have 2 Lyman & 2 T/C single cavity .490" RB molds, none of which casts exactly .490" or the same weight ball.  A competitive BP shooting friend has convinced me to weigh RB's, and this has motivated me to weigh all bullets I cast.  If you have a hand held calculator with a statistics program (to determine the mean/average and standard deviation) and a digital scale, this takes less time, but it is tedious.  What I do is weigh a sample of 25 - 30  RB's or elongated bullets, enter the weight of each into the calculator, and determine the Mean & SD.  I then weigh all of the bullets, keeping only those that are plus or minus 1 SD.  For more critical shooting, e.g., a match, you can be more restrictive if you wish, separating those within 1/2 SD and save the rest for practice.

[jamesthomas]

 Thanks guys! I've  just cast about 1500 rbs. I got them to weigh between 176 to 178 grns so thats right in the ball park had to remelt about 200 to get this range. Plan on going to some local shoots as soon as I get my trigger pull adjusted to around 3 pounds right now it's about 8 to 10 way to heavy for offhand shooting!

[Dphariss]

How much spread in .50 cal. cast rb weights should you allow for ? I'm using some roofing lead I've have so it's real soft lead.

1 grain plus or minus if you are serious.
A good mold and a good lead pot should do this with consistent casting process.
Percentage of weight means nothing, 1% of a 500 grain bullet is 5 grains and you don't want to waste time shootine bullets that are 5 grains light. Anything over 1 grain light indicates increasingly serious internal problems as the bullets get lighter.
Yeah, I have actually machined bullets down .010" at a cut to find out what made them light. The result is that I consider anything more that 1 grain below normal to be scrap to be recast.
Round balls are more forgiving but why shoot projectiles that can't be trusted.

Dan